The Hubble-Type Outflows from the High-Excitation, Polypolar Planetary Nebula NGC 6302

Spatially resolved profiles of the Hα and [N II] lines have been obtained at unprecedented signal-to-noise ratios over the outflowing lobes of the high-excitation, polypolar planetary nebula NGC 6302. A deep image in the light of [N II] λ6584 was also obtained of the extremities of the prominent northwestern lobe. The Manchester Echelle Spectrometer combined with the 2.1 m San Pedro Martir telescope (Mexico) was used for these observations. First, an accurate value of the systemic heliocentric radial velocity of Vsys = -29.8 ± 1 km s-1 has been established. Also, from "velocity ellipses" across its diameter from previous observations, the parallel-sided northwestern lobe is shown to have a circular section with a tilt of its axis to the plane of the sky of 12.°8. With this starting point the position-velocity arrays of profiles have been very closely simulated, using the SHAPE code, with Hubble-type outflows. The faint extremities of the northwestern outflow are shown to be expanding at ≥600 km s-1. The prominent lobes of NGC 6302 have then been generated in an eruptive event with a dynamical age of 1900 yr for an expansion proper-motion distance of 1.04 ± 0.16 kpc, as measured here by comparing a 1956 image with one taken in 2002. Kinematical evidence of a high-speed "skirt" around the nebular core, expanding nearly orthogonally to the lobes, is also presented, as are the unusual motions at the western extremities of the northwestern lobe.